Effects of protein intake and gender on body
composition changes: a randomized clinical weight
loss trial
Limited data on sex differences in body composition changes in response to higher proteindiets (PRO) compared to higher carbohydrate diets (CARB) suggest that a PRO diet helpspreserve lean mass (LM) in women more so than in men.ObjectiveTo compare male and female body composition responses to weight loss diets differing inmacronutrient content.DesignTwelve month randomized clinical trial with 4mo of weight loss and 8mo weightmaintenance.SubjectsOverweight (N = 130; 58 male (M), 72 female (F); BMI = 32.5 +/- 0.5 kg/m2) middleagedsubjects were randomized to energy-restricted (deficit ~500 kcal/d) diets providingprotein at 1.6 g.kg-1.d-1 (PRO) or 0.8 g.kg-1.d-1 (CARB). LM and fat mass (FM) weremeasured using dual X-ray absorptiometry.
Body composition outcomes were tested in arepeated measures ANOVA controlling for sex, diet, time and their two- and three-wayinteractions at 0, 4, 8 and 12mo.
Results:
When expressed as percent change from baseline, males and females lost similar amounts ofweight at 12mo (M:-11.2 +/- 7.1 %, F:-9.9 +/- 6.0 %), as did diet groups (PRO:-10.7 +/- 6.8 %, CARB:-10.1 +/- 6.2 %), with no interaction of gender and diet. A similarpattern emerged for fat mass and lean mass, however percent body fat was significantlyinfluenced by both gender (M:-18.0 +/- 12.8 %, F:-7.3 +/- 8.1 %, p <0.05) and diet(PRO:-14.3 +/- 11.8 %, CARB:-9.3 +/- 11.1 %, p <0.05), with no gender-dietinteraction.
Compared to women, men carried an extra 7.0 +/- 0.9 % of their total body fat inthe trunk (P <0.01) at baseline, and reduced trunk fat during weight loss more than women(M:-3.0 +/- 0.5 %, F:-1.8 +/- 0.3 %, p <0.05). Conversely, women carried 7.2 +/- 0.9 %more total body fat in the legs, but loss of total body fat in legs was similar in men andwomen.
Conclusion:
PRO was more effective in reducing percent body fat vs.
CARB over 12mo weight loss andmaintenance. Men lost percent total body fat and trunk fat more effectively than women.
Nointeractive effects of protein intake and gender are evident.
Author: Ellen M EvansMina C MojtahediMatthew P ThorpeRudy J ValentinePenny M Kris-EthertonDonalkd K Layman Credits/Source: Nutrition &Metabolism 2012, 9:55
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